When I manually (by mouse) write the automation of Serum in Cubase, directly in the automation-lane, automation works as desired. When I write the automation by moving a parameter in Serum, in my case Filter Cutoff, with my mouse, while playing between the locators in Cubase, the automation visually gets written but on playback there is no automation happening. As a matter of fact, all automation is then lost. Only after closing Cubase and opening the project again I can proceed with what I described in the first line of this message.
It looks like I have an issue that occurs between Cubase 10.5 and Serum. I hope someone solved this issue already.
I have posted this issue also on the Xfer Serum forum.